Network Acceleration Aids Disaster Recovery

To be properly readied for any disaster, it is essential to be able to quickly get mission-critical servers and applications up and running. It's one of the reasons why the virtualization of both servers and desktops has become such a central part of many business continuity and disaster recovery (BC/DR) plans. If those virtualized servers and systems are stored at another site, and backups are regularly performed, it is possible to have a great percentage of the business back up and running within hours, rather than weeks.

Yet, more businesses are finding a rapid growth in the amount of bandwidth needed to maintain near-real-time synchronization of data and systems across their wide-area networks (WANs).

Rising bandwidth demand likely explains, in part, why investment in networking is growing, while many parts of IT spending are stagnating. Research firm Forrester Research found in a recent survey that 53 percent of organizations plan on increasing their budget for networks and communications equipment. That was topped only by the 58 percent that pla to increase spending on service management, while spending on servers, storage, and client systems all face significant declines.

"We are seeing enterprises increase network and telecommunication spend; much of that is earmarked for building bandwidth efficiencies," Forrester analyst Chris Silva said during a recent Webcast. "Many companies had thought of increasing bandwidth effectiveness by adding more bandwidth, when in fact that is not always the case."

That was the exact conundrum recently faced by the maker of specialty products for concrete construction, Dayton Superior Corp. The company has 40 locations in the U.S., its primary data center located in its Dayton, Ohio, headquarters, and an outsourced BC/DR site located in Chicago. While replicating its virtualized servers and data across the two sites, the company found it hit a bandwidth bottleneck.Dayton Superior relies on a high-speed DS3 line (45 Mbit/s) to connect the sites, and uses VMware Site Recovery Manager to replicate its EMC storage system, roughly 40 Windows 2003 servers, and a number of Citrix and UNIX servers.

"The challenge, when you reopen disaster recovery discussions, is that the business always finds more and more things that it wants available very quickly after an incident," says Mark Hickey, director of IS at Dayton Superior. "The bottom line is that you always end up with more services than you thought you'd have in the beginning of planning. And if it's applications, data, and services that the users have to have within 24 hours, then you are looking at a hot data backup, with spare systems ready to go."

Because Dayton Superior's BC/DR site also operates as a secondary data center, Hickey found that bandwidth availability was quickly getting lean. "When you cut the bandwidth in half to make it available for production systems, and then the rest is for backup and recovery, you find that you quickly run out of space," he says. "We considered adding either additional bandwidth or finding a WAN optimization technology that would get us the additional capacity we needed."

Ultimately, Dayton Superior chose to optimize with an NX WAN acceleration appliance from Silver Peak Systems. The NX WAN acceleration appliances utilize a couple of technologies to maximize bandwidth throughput. First it de-duplicates traffic so that repetitive data isn't transmitted over the WAN, and stores commonly transmit files on local drives or within the appliance itself. Second, it also utilizes common traffic compression algorithms to maximize bandwidth.

Analyst Silva says Silver Peak combines two common, but historically separate, approaches to WAN optimization: the use of caching and compressing to manage de-duplication, along with protocol acceleration and traffic management. While caching and compression help to boost replication, backup, and content-intensive applications, protocol acceleration is most effective for Web-based applications and dynamic content.The ultimate benefit for Dayton Superior: bandwidth savings through reducing sent data and eliminating unnecessary network roundtrips, says Hickey. "When we deployed the appliance, we realized an 80 percent reduction, on average, in network usage," he says. "In some cases, we reduced traffic by 10 to 15 times."

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